Teruki Kamon CMS Results: Higgs and SUSY December 2012 1 CMS: Higgs and SUSY Mitchell Institute for Fundamental Physics and Astronomy Texas A&M University & Department of Physics Kyungpook National University HEP Seminar, University of Tukuba December 5, 2012
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CMS Results: Higgs and SUSY - …people.physics.tamu.edu/.../121205_Tsukuba_Higgs+SUSY_v2b.pdfa Higgs boson mass hypothesis with a local significance of 4.1 sigma. The global significance
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Teruki Kamon
CMS Results:
Higgs and SUSY
December 2012 1 CMS: Higgs and SUSY
Mitchell Institute for Fundamental Physics and Astronomy
Keep in mind they are preliminary results; Keep in mind they are small numbers; Keep in mind we will run in the next year.
Newly approved
analysis including
VBF Hgg (was not
in the CERN
seminar)
Enhanced sensitivity
in the low mass
region
Global p-value (with
LEE) is 2.1 sigma
January 2012
December 2012 10 CMS: Higgs and SUSY
We have observed a new boson
with a mass of
125.3 ± 0.6 GeV at 4.9 s !
[GeV]4lm
Eve
nts
/ 3
GeV
0
2
4
6
8
10
12
[GeV]4lm
Eve
nts
/ 3
GeV
0
2
4
6
8
10
12 Data
Z+X
*,ZZgZ
=126 GeVHm
m, 2e2m7 TeV 4e, 4
m, 2e2m8 TeV 4e, 4
CMS Preliminary -1 = 8 TeV, L = 5.26 fbs ; -1 = 7 TeV, L = 5.05 fbs
[GeV]4l
m80 100 120 140 160 180
July 4, 2012
December 2012 11 CMS: Higgs and SUSY
Higgs Signal Strengths
Production and decay rates could be
deviated from the SM expectation
through SUSY particles in loop-
induced processes
Could be …
December 2012 12 CMS: Higgs and SUSY
SUSY
SUSY is : a) Supersymmetrized Standard Model
(“Democratic” solution between Fermions and Bosons);
b) An elegant solution to solve the problem associated with the Higgs mass around 1 TeV;
+
Unification!
c) Beautifully connecting the Standard Model with an ultimate unification of the fundamental interactions around 1 TeV;
d) Cosmologically consistent with a Dark Matter candidate around 1 TeV.
e) There must be a light Higgs boson:
below ~150 GeV.
13
Supersymmetry (SUSY)
CMS 2011 Physics
Very rare decays Searches for new physics with MET
Precision measurements
No signs of new physics (yet)
even in 2012
14 December 2012 14 CMS: Higgs and SUSY
FCNC in Bsmm
Br(Bsmm)
2
+
15
This is one of interesting rare decays to test new physics such as SUSY:
Br(Bsmm)SM ~ 3 x 10-9
Br(Bsmm)SUSY ~ Br(Bsmm)SM x (10 ~ 1000)
December 2012 15 CMS: Higgs and SUSY
LHCb at HCP2012
New
December 2012 16 CMS: Higgs and SUSY
Implications
[Light 3rd Generation SUSY Particles] Light stop direct stop production
Light stau direct EWKino production
[Lightest SUSY Particles] Higgsino LSP chargino and neutralinos below 200 GeV, with mass
splittings of order 10 GeV. It is very difficult for LHC to observe these
particles. See, for example, Papucci, Ruderman, Weiler, arXiv:1110.6926; Baer, Barger, Huang, Tata, arXiv:1203.553
[Ruling out Minimal Models] mGMSB and mAMSB are ruled out;
mSUGRA : A0 = 0 is ruled out; stau-neutralino is mostly ruled out. See, for example, Howard Baer, Vernon Barger, Azar Mustafayev, “Neutralino dark matter in mSUGRA/CMSSM with a 125 GeV light Higgs scalar”, JHEP 1205 (2012) 091, DOI: 10.1007/JHEP05(2012)091, e-Print: arXiv:1202.4038 [hep-ph]
[Moving to Non-minimal Models]
Where We Stand …
17 December 2012 CMS: Higgs and SUSY
SUSY Probe Metric at LHC
Minimal SUGRA
Non-Universal
SUGRA
),tan,,( 01/20
2~0
1
Ammh
D
),,tan,,( 01/20
2~0
1
m
Ammh D
July 4, 2012
E
Dec 13, 2011
Tevatron
Precision
We test a minimal case first, followed by “non-minimal” cases.
December 2012 18 CMS: Higgs and SUSY
December 2012 19 CMS: Higgs and SUSY
CMS Detector
g
m
g
m m
m
December 2012 20 CMS: Higgs and SUSY
CMS Detector
December 2012 21 CMS: Higgs and SUSY
Excellent tracker, High resolution EM calorimeter,
Redundant muon detector, Good hadron calorimeter
Particle ID
December 2012 22 CMS: Higgs and SUSY
Collider Detectors
ATLAS CMS CDF II D0 II
Magnetic
field
2 T solenoid +
toroid (0.5 T barrel
1 T endcap)
4 T solenoid +
return yoke
1.4T solenoid 2T solenoid
+ toroid (1.8T)
Tracker Si pixels, strips +
TRT
σ/pT ≈ 5x10-4 pT +
0.01
Si pixels, strips
σ/pT ≈ 1.5x10-4 pT +
0.005
Si strips + drift
chamber
Si strips +
scintillating fiber
EM
calorimeter
Pb+LAr
σ/E ≈ 10%/√E +
0.007
PbWO4 crystals
σ/E ≈ 3%/√E 0.003
Pb+scintillator
σ/E ≈ 13.5%/√E
0.015 in barrel
U+LAr
Hadronic
calorimeter
Fe+scint. / Cu+LAr
(10λ)
σ/E ≈ 50%/√E
0.03
Brass+scintillator (7
λ + catcher)
σ/E ≈ 100%/√E
0.05
Iron+scintillator
σ/E ≈ 50%/√E 0.03
in barrel
U+LAr (Cu or
stainless in outer
hadronic)
Muon σ/pT ≈ 2% @ 50GeV
to 10% @ 1TeV
(ID+MS)
σ/pT ≈ 1% @ 50GeV
to 10% @ 1TeV
(DT/CSC+Tracker)
Rapidities to 1.4 Rapidities to 2.0
December 2012 23 CMS: Higgs and SUSY
All physics objects (charged hadrons, neutral hadrons, g, e, m, t jets, MET) are reconstructed with the PF algorithm.
Basic idea:
– Reconstruct and identify all different types of particles
– Apply corresponding calibrations
– The list of “particles” is given to the jet clustering and missing ET
(MET) reconstruction algorithm
Particle Flow (PF) Algorithm
December 2012 24 CMS: Higgs and SUSY
Particle Flow (PF) Algorithm
Improvements in all the reconstructed objects
Jets and MET : resolution and energy scale improved by 2-5
times w.r.t. calorimeter based reconstruction
Lepton isolation : background rejection improved by a factor 2 at
same efficiency
Exellent reconstruction and identification for th
See the following pages for basic concept December 2012 25 CMS: Higgs and SUSY
All physics objects (charged hadrons, neutral hadrons, g, e, m, t jets, MET) are reconstructed with the PF algorithm.
Basic idea:
– Reconstruct and identify all different types of particles
– Apply corresponding calibrations
– The list of “particles” is given to the jet clustering and missing ET
(MET) reconstruction algorithm
Charged hadrons
~65% of jet energy
Use the high resolution tracker
~1% at 100 GeV
December 2012 26 CMS: Higgs and SUSY
Photons
~25% of jet energy
Use high resolution / good
granularity ECAL
Granularity: 0.02 ()
Energy resolution: ~2%/E
December 2012 CMS: Higgs and SUSY
Neutral hadrons
~10% of jet energy
Use HCAL
Granularity: 0.1 ()
Energy resolution: ~100%/E
December 2012 CMS: Higgs and SUSY
Jet:
Charged hadron (solid)
Photon (dashed line)
Neutral hadron (dotted line)
Particles clustered in jets
December 2012 CMS: Higgs and SUSY
December 2012 30 CMS: Higgs and SUSY
7 TeV: Phys. Lett. B 710 (2012) 403
7+8 TeV: Phys. Lett. B 716 (2012) 30
and CMS-HIG-12-015
and https://twiki.cern.ch/twiki/bin/view/CMSPublic/Hig12015TWiki
December 2012 31 CMS: Higgs and SUSY
L = 5.1 fb-1 (7 TeV) + 5.3 fb-1 (8 TeV)
pT1 > m(gg)/3 & pT2 > m(gg) /4 ; M = 2Eg1 Eg2 (1 – cosq) Photon ID MVA based on shower topology and isolation;
Di-photon MVA classifications with signal-like
kinematics, good mass resolution, per-event vertex
probability, photon-likelihood.
6 categories optimized for the best expected limits (4 di-
Fakes – largely controlled by isolation, lateral shower shapes,
electron track veto, Ehad/Eg
BDT trained on simulated Higgs and g+jet events
Highlights of Di-photon Analysis
December 2012 32 CMS: Higgs and SUSY
PbWO4 Crystals in CMS
December 2012 33 CMS: Higgs and SUSY
M(gg) Resolution : dE/E
December 2012 34 CMS: Higgs and SUSY
5x5 crystals
3x3 crystals
(uncorrected) 3x3 crystals
(corrected)
Simulation
Calibration
December 2012 35 CMS: Higgs and SUSY
Calibration
December 2012 36 CMS: Higgs and SUSY
M(gg) Resolution : Vertexing
December 2012 37 CMS: Higgs and SUSY
pT1 > m(gg)/3 & pT2 > m(gg) /4
Photon ID using MVA based on
shower topology and isolation;
Di-photon MVA classifications
with signal-like kinematics, good
mass resolution, per-event
vertex probability, photon-
likelihood.
6 categories optimized for the
best expected limits (4 di-photon
MVA categories; 2 di-jet tagged
categories).
BDT trained on simulated Higgs
and g+jet events
Di-photon Categories
December 2012 38 CMS: Higgs and SUSY
Di-jet tagged Di-Photon
Two (one in 2011) classes of events (according to mjj) with S/B an order
of magnitude larger than inclusive classes Sensitivity increases by
10% December 2012 39 CMS: Higgs and SUSY
Decay products
Highest energy jets in the event selected with large pseudo-rapidity
gap Enriches in VBF content and rejects background
Di-photon BG Modeling Background model fit to the m(gg) distribution for the 6 categories,
together with a simulated signal (mH = 125 GeV). The sum of the event
classes together with the sum of the five fits is also shown.
Background modeling: polynomial shape with order from 3 to 5.
Potential bias from background model is less than 20% of statistical
uncertainty.
December 2012 40 CMS: Higgs and SUSY
[First 4 classes] A 5th order polynomial function in 100-180 GeV is found to be unbiased in either excluding or finding the Higgs boson signal, compared to the statistical uncertainties of the fit. [VBF] A 2nd (3rd) order polynomial function
[Consistency check] The di-photon mass spectrum that is observed after the full event selection is found to agree with the distribution predicted by MC simulation, within the uncertainties on the cross sections of the contributing processes which is estimated to be about 15%.
Di-photon BG Modeling
Cat 0 Cat 1 Cat 2
Cat 3
December 2012 41 CMS: Higgs and SUSY
VBF tight VBF loose
Di-photon S/B-weighted Mass
Each event class is weighted by its S/(S+B) only for
visualization purpose
December 2012 42 CMS: Higgs and SUSY
Mgg= 125.1 GeV 0.4 (stat) 0.6 (syst)
July 4: 125.3 ± 0.6 GeV (stat+syst)
Di-photon : P-Value
125 GeV … The largest excess (above the expected SM background) for
a Higgs boson mass hypothesis with a local significance of 4.1 sigma.
The global significance of observing an excess with a local significance
greater than 4.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 3.2 sigma.
December 2012 43 CMS: Higgs and SUSY
Di-photon Signal Strength
Combined best-fit signal strength for
a SM Higgs boson mass hypothesis of
125 GeV:
s/sSM = 1.56 + 0.43
Signal strength is compatible across
signal categories.
December 2012 44 CMS: Higgs and SUSY
1
Di-photon Summary Expected exclusion limits on s x Br(HSMgg) at 95% CL are
0.76 times the SM cross section at ~125 GeV.
The SM Higgs boson (HSMgg) in the mass ranges [114-
211], [129-132], [138-149] are excluded at 95% CL.
The largest excess above the expected SM background is
observed for a Higgs boson mass hypothesis of 125.1
0.4 (stat)0.6 (syst) GeV with a local (global) significance
of 4.1 (3.2) sigma.
More data are required to ascertain the nature of this